Electron tube



ug. 2, 1949. w. soLLER 2,477,667

. ELECTRON TUBE Original Filed Aug. 19, 1945 SECONDA/7 Y Z'C TRO/V INVENTOR.

Patented Aug. 2, 1.949

ELECTRON TUBE VJalter Soller, Cincinnati, 'Gf-hin, assigner lof -onehalf to William H. Woedin, Jr., San lMateo, Calif.; Nora A. Woodin, executrix of said Williana El. Woodin, Jr., deceased @riginal application August 19, 15943, `Serial No. 499.12.60. Bivided Aand this application August 28, 1944, Serial No. 551,514

(Cl. Z50-174) .6 Claims. .1

My invention relates broadly :to electron tubes and more particularly to a Adeection type of 'secondary electron emission tube for wide application in the velectronic industry.

This 'application is a division of my application Serial No. 499,260 filed August 19, 1943 for Electron -t-ube.

'One of the objects of my invention is to provide a construction of deflection type secondary electron emission tube .hav-ing associated input and output lcircuits wherein substantially complete isolation of the input from :the output circuit is e'ected.

Another object vof my invention is to provide an improved construction :of secondary yemission electron beam controlled tube having a `pair of apertured disc-like focusing electrodes for accurately controlling the movement of an electron beam of 4circular section with respect to a'secondary :electron discharge electrode assembly.

A further object of my invention is to provide a Asecondary `electron discharge tube having an arrangement of electrodes :in which a high .degree -of :sensitivity :is obtained by eecting a large change in vsecondary electron `emissionnfor aslight change in .deection of an electron beam.

Still another object of my invention is to provide a construction of secondary electron dis- -charge .electrode :assembly comprising an annular hooded collecting plate and an annular disc-like secondary .electron emitting plate disposed therein in vassociation with a grid electrode and disc-like plate collecting electrode.

Other and further objects of vmy invention reside in 'the construction and arrangement of the elements of deiiection type secondary electron emission Vtubes as set forth more tfullyjn the specication hereinafter following by reference to th accompanying drawings, in which:

Figure lis a vlongitudinal sectional view through the secondary emission tube of my invention showing the disc-like focusing `electrodes and the secondary discharge electrode assembly against which the -focused beam is directed; Fig. 2 is a transverse sectional view taken on line 2-2 -of Fig. 1; Fig. `3 isa transverse .sectional view taken on :line 3 3 of Fig. 1,; Fig. 4 is a longitudinal sectional View vtaken through a modi-ed form of secondaryemission tube embodying my invention and showing an annular -plate electrode having .an aperture rtherein of larger size than the struc- .ture shown in Figs. Y1 3 utilized in conjunction with aconventional type-of sweep control :for the shea-m tube; and Fig. 5 is a transverse -sectional viewtaken on line'S- of Fig. 4.

In Figs. 1 3 I have shown the system of my invention applied to an electron beam amplifier tube. I have termed this an electron beam ramplifier tube rather than a deflection tube because in this arrangement I provide an electron beam generator of the electron gun type schematically represented at |913, which propagates an electron beam of circular section through the apertured electrodes It and |96. VApertures are indicated at |D5a. and lia. The apertured electrodes |65 and |06 are curved as shown, and are connected to the input circuit 'et and serve as focusing electrodes for the electron beam ,propagated from electron gun |915. As the current changes in the input circuit 4i), the beam is Icaused to change from lan accurate focus to an out of focus condition.

'I'he .electron Vbeam is directed toward the disclike secondary electron emitting plate member |08, `centrally .apertured at lSa as shown in Fig. 3. Thedisc-like secondary electron emitting plate l| 68 is surrounded by a flared cylindrical collector electrode |09, shaped as indicated. The electrode |09 also encloses grid electrode 54 and is specially related to plate electrode 55. The electron beam striking plate electrode 55 when passing through aperture |980@ does not cause the emission of electrons from the annular disclike plate |93 but when the beam is drawn over against the surface of annular disc-like secondary electrode |08 the electronic bombardment causes the emission of secondary electrons that are drawn over to the ared cylindrical collector electrode |99. The original beam is circular in cross section as it is formed and it is propagated from electron gun |114 and passes through the apertures 105e and tuta in focusing electrodes .|05 and .|06 and -through `aperture |0801. in elecrIhe :potential .on the two input plates |95 and |06 allows the beam to focus exactly in the center of the plate |98 and, therefore, passes through the aperture Ita in plate i538 and strikes plate electrode 55. Any secondary electrons which would be emitted remain there because grid 5d is held at a lnegative potential by battery 57. vAs vthe input increases the .beam of electrons is thrown out of focus by the voltage on the two circular spherical shaped plates m5 and |66. This changes ,the focus of the beam so that it now 'does not focus in the aperture llla in the plate |08 but is spread out as it strikes plate |08. The extent of this spreading out iscontrolled by the input potentials on plates |95 and |06. In `this Way a similar result is obtained as with the deflection method, although I do not limit my invention to deflection and can use any means by which a change in emission from plate |08 can be secured to the output circuit. Accordingly it will be understood that my invention is not restricted to a rectangular cross section beam but is equally applicable to a circular section beam.

In Figs. 4 and 5 I have shown my invention applied to an electron beam tube in which an electron beam of circular section emanating from electron gun |04 may pass through an enlarged aperture ||5 in the disc-lil e secondary electron emitting plate M and be displaced under control of deflection plates '|-8 to strike the annular face of plate IIA for release of secondary electrons to the lared cylindrical collector plate |59. The structure illustrated in Figs. 4 and 5 diiers from the structure described in Figs. 1 3 by reason of the enlarged aperture H5 in plate H4. Greater sensitivity is obtained by enlarging the aperture in plate l!!! as a large change in secondary emission is secured fby a slight change in the deflection of the beam. The arrangement of the electrodes in the tube of Figs. 4 and 5 and the circuits interconnecting said electrodes are similar to the arrangement shown in Figs. 1-3.

The secondary emission electron beam tube of my invention has wide application in electrical control circuits and is applicable to regenerators,

oscillators, feed-back circuits, reverse feed-back circuits, D. C.A. C. amplification systems and various forms of frequency multipliers or frequency division systems. The outstanding advantage of the electron beam tube of my invention is complete isolation `of the input circuit from the output circuit to meet such conditions, for

, example, as low power input, high voltage ampliication, high sensitivity operation or operation at high frequency. This isolation feature permits large voltages on the output with no possibility of the output voltages aiecting the input; ex-

tremely low impedance not possible in the conventional grid controlled tube; and sensitivity even with large output currents.

VIn the form of my invention shown in'Figs. 1-3 thecontrol of the electron beam of circular section is effected by the shaped apertured electrodes It and H56. These electrodes are disclike having partially spherical surfaces equidis- 'tant one from the other and formed on the radii having the same center. The electrostatic control of the electron beam that is produced by the partially spherical electrodes |05 and E06 serves to accurately center the electron beam through the aperture |680, in electron emitting plate |08 under normal conditions. Under conditons of unbalance, however, or change in electrostatic capacity between plates |05 and |05;

the electron beam is angularly shifted to variably activate portions of the secondary emitting annular electrode |08 to produce the secondary emission which is collected by the flared cylindrical collector plate |69 as heretofore explained. The secondary electron collecting plate |09 is provided with an outwardly diverging skirt which is directed toward the electron beam generator and which is integral with the cylindrical portion of the electrode that surrounds the secondary electron emitting plate Hi8 and the grid electrode 54. This same arrangement is provided in the construction of tube shown in Figs. 4 and 5 wherein the outwardly diverging skirt of the secondary 'electron collecting plate |09 offers minimum interference with the primary electrons in the electron beam propagated from the electron gun |04 while providing maximum collecting area for the secondary electrons released from the activated portions of the annular secondary electron emitting plate |4.

While I have described my invention in certain preferred embodiments, I realize that modifications may be made in the arrangement and method employed and I desire that it be understood that vno limitations upon my invention are intended other than may be imposed by the scope of the appended claims.

What I claim and desire to secure by Letters Patent of the United States is as follows:

1. An electron tube system comprising an electron discharge rdevice for propagating an electron beam, a pair of apertured electrodes disposed in the path of said electron beam for variably controlling the focus of said beam according to variations in input current, a plate system comprising a centrally apertured disc-like plate aligned with the apertured electrodes, a secondary electron emitting coating carried by the surface of said disc-like plate, a grid member mounted adjacent to said centrally apertured disc-like plate and charged at negative potential with respect thereto, a plate electrode mounted adjacent to said grid member and charged at positive potential with respect thereto, and ilared cylindrical secondary electron collecting plate surrounding said disc-like plate,` said collecting plate having an outwardly diverging skirt directed toward said electron discharge device out of the path of said electron beam and providing a relatively wide collecting area for secondary electrons emitted by said disc-like plate.

2. An electron discharge system comprising an electron discharge device for propagating an electron beam, means for controlling the angular sweep of the electron beam, a secondary electron emitting plate disposed in the path of said electron beam, said plate being apertured for the normal passage of said electron beam, a grid member disposed behind said plate and maintained at negative potential with respect thereto, a plate electrode mounted adjacent said grid Ymember and aligned with said secondary electron ondary electron collecting electrode surrounding said secondary electron emitting plate and grid member and having an outwardly diverging skirt directed toward said electron discharge device out of the path of said electron beam and providing a relatively large collecting area for receiving secondary electrons discharged by said secondary electron emitting plate under bombardment of said electron beam.

3. An electron discharge system comprising an electron discharge device for propagating an electron beam, means for controlling the angular sweep of the electron beam, a secondary electron emitting plate disposed in the path of said electron beam, said plate being apertured for the normal passage of said electron beam, a grid member disposed behind said plate and maintained at negative potential with respect thereto, a plate electrode mounted adjacent said grid member and aligned with said secondary electron emitting plate and maintained at positive potential with respect to said grid member, and a substantially cylindrical secondary electron `collecting electrode surrounding said secondary electron electron discharge device out of the path of said electron beam and providing a relatively large collecting area for receiving secondary electrons discharged by said secondary electron emitting plate under bombardment of said electron beam.

4. An electron discharge system comprising an electron discharge device for propagating an electron beam, means for controlling the angular sweep of the electron beam, a secondary electron emitting plate disposed in the path of said electron beam, said plate being apertured for the normal passage of said electron beam, a grid member disposed behind said plate and maintained at negative potential with respect thereto, a plate electrode mounted adjacent said grid member and aligned with said secondary electron emitting plate and maintained at positive potential with respect to said grid member, and an annular secondary electron collecting electrode surrounding said secondary electron emitting plate and said grid member and having an outwardly diverging skirt directed toward said electron discharge device out of the path of said electron beam and providing a relatively large collecting area for receiving secondary electrons discharged by said secondary electron emitting plate under bombardment of said electron beam.

5. An electron discharge system comprising an electron discharge device for propagating an electron beam, means for controlling the angular sweep of the electron beam, a secondary electron emitting plate disposed in the path of said electron beam, said plate being apertured for the normal passage of Said electron beam, a grid member disposed behind said plate and maintained at negative potential with respect thereto, a plate electrode mounted adjacent said grid member and aligned with said secondary electron emitting plate and maintained at positive potential With respect to said grid member, and an annular secondary electron collecting electrode having an outwardly diverging skirt directed toward said electron discharge device out of the path of said electron beam and having a portion thereof surrounding said secondary electron emitting plate and said grid member for receiving secondary electrons discharged by said secondary electron emitting plate under bombardment of said electron beam.

6. An electron tube system comprising an electron discharge device for propagating an electron beam, a pair of electrodes disposed in the path of said electron beam for Variably controlling said beam according to variations in input current, a plate system comprising a centrally apertured disc-like plate aligned with the said pair of electrodes, a secondary electron emitting coating carried by the surface of said disc-like plate, a grid member spacially related to said centrally apertured disc-like plate and charged at negative potential with respect thereto, a plate electrode mounted adjacent said grid member and charged at positive potential with respect thereto, and an annular secondary electron-collecting plate surrounding said disc-like plate, said collecting plate having an outwardly diverging skirt directed to- Ward said electron discharge device out of the path of said electron beam and providing a relatively wide hood around said disc-like plate forming a collecting area for secondary electrons emitted by said disc-like plate.

WALTER SOLLER..

REFERENCES CITED The following references are of record in the ile of this patent:

UNITED STATES PA'I'ENTS Number Name Date 1,559,460 Ruben Oct. 27, 1925 2,069,441 Headrick Feb. 2, 1937 2,197,652 Statz et al Apr. 16, 1940 2,257,795 Gray Oct. 7, 1941 2,266,639 Hollmann Dec. 16, 1941 

